Cell culture chambers have been used by biologists to study the growth of cells. By growing cells in a cell culture chamber, cell growth can be continuously observed under a light microscope. Early cell culture chambers utilized concave slides for viewing cell cultures. However, this type of chamber is unsuitable for cells which require continuous replenishment of gas and/or liquid phases of the growth medium. Furthermore, the concave structure of the cell culture chamber introduces undesirable optical effects when viewing the cells under a light microscope. In response, flow-through cell culture chambers have been developed through which aerated growth medium could be continuously supplied.
In order to be suitable for use in most types of light microscopes, the flow-through cell culture chamber should have the following characteristics: (1) optically flat, strain-free, parallel surfaces, with a fixed viewing thickness; (2) a closed culture chamber to safely observe, handle and contain human pathogens or other hazardous materials; (3) an easily sterilizable culture chamber; and (4) the materials forming the walls of the culture chamber should be biologically inert and non-toxic.
A flow-through culture chamber was disclosed in Poynton, et. al., Experimental Cell Research 60, pages 109-114 (1970), which utilizes compressible spacers to maintain the space between the glass surfaces of the cell culture chamber. The two pieces of glass are placed on either side of the compressible spacer and then set screws or similar devices are tightened around the periphery of the chamber to produce a seal. However, it is difficult to tighten the screws uniformly to produce a chamber which is strain free and in which the two pieces of glass are parallel. Furthermore, liquid medium is replaced in the chamber by inserting syringes through the compressible spacer, which is undesirable.
U.S. Pat. No. 3,726,597 discloses a flow-through cell culture chamber which is sealed using a compression ring attached to the chamber. Installation of the compression ring requires the use of a special pair of pliers. Installation of the compression ring is very difficult, and often, when installing the compression ring one or both of the cover slips shatter. Furthermore, if the pliers slip, damage can be done to the inlet or outlet tubing to the culture chamber. This type of flow-through cell culture chamber is difficult to clean, assemble, and use on an inverted fluorescent microscope. Thus, there is a need for a simple and efficient flow-through culture chamber.